Crank-shaft.



A. BIEDLER.

- CRANK SHAFT.

APPLICATION FILED JULY 1. 1911.

Patented Jan. 22,191&

hrexl/ ari' ALOIS RIEDLER, OF BERLIN, GERMANY.

CRANK-SHAFT.

npplication'filedjuly'i,1917. $eriaINo.1'79,216.

To all whom it may concern.-

Be 1 t known that I, Dr. Anois RIEDLER, a sub1ect of the- Emperor of Germany, residing at No. 7, Rauchstrasse, Berlin, Germany,

have invented certain new and useful Improvements in Crank-Shafts; and I ,do hereby declare the following to be a clear, full, and exact description'ofthe invention, such-as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawing, and to letters or figures of reference marked thereon, which form a part of this specification.

The present invention has reference to certain new and useful improvements in crank shafts, and relates more particularly to a cranked shaft, whose crank portion 1 proper, of right-angle design, is of relatively narrow construction without the bearing surfaces being unduly shortened.

It has been proposed in prior art to ob tain this reduction in longitudinal extent.

by slantingly directing the crank arms or webs toward one another ;'but such converg ing crank arms are stressed rather unfavorably and for this reason must be made comparativelywide. 'In. engines with small crank radius a" crank with such converging webs can not be used, for the reason that the space between journal and crank pin is insufficient to accommodate a sufiiciently wide crank-arm of slanting extent.

In one-armed crank shafts the distance J between the crank arm and the center of the connecting rod has been reduced by providing an annular, closed recess in the crank arm about the crank pin; but this construc tion is not suitable for cranked shafts, for the reason that the ordinary two-part journal bearings or brasses can not be introduced "into the oppositely disposed, closed recesses The use ofsuch a lround closed recesses in cranked shafts requires obviously, the employment of multipart bearings.

According to this invention this drawback is effectively obviated. My new construction of recess is such that the ordinary two-part bearings'or brasses can readily be used, and that at the same time the length of the crank shaft including the rectangular cranked portion can be materially reduced.

-The recesses in the crank webs are substantiall horse-shoe shaped and are provided on t e-broad side faces of thewebs in such Specification of Letters Patent.

Q Patented Jan. as, 1918.

manner that their open ends face oppositely outwardly in the longitudinal. axis of the webs. By this arrangement the crank arms are'given a favorable stress cross-section and can be made rather strong, while the smallest size web, as regards the depth of recess,

even when their side faces are parallel, is wider by the depth of the second recess of the same web than in prior constructions of such cranks. i

In the accompanying drawing Figure 1, shows side elevation of a crank according to my invention,

Fig. 2 a cross-section therethrough;

Fig.3 represents a plan view of a doublearm crank, and

Fig. 4 a longitudinal section therethrough;

Fig. 5 shows a side elevation of a two throw crank construction.

The crank shaft comprises in the usual manner the journals 1, the crank arms or webs 2, and the. crank pin 3 The webs are shown as being parallelly disposed, resulting in a rectangular crank portion.

The reduction in the longitudinal extent is obtained by providing the crank webs on either side face with approximately horseshoe-shaped recesses a, surrounding the re spective journal or pin ends, into which engage the bearings or brasses.

In a twoarm crank with such recesses 4 (each of the depth 5), a reduction is obtained equal tothe sum of the depths of the four recesses. The bending moment's under otherwise equal stresses will become smaller. The crank arms, provided with such recesses 4, show a favorable U-cross-section, with raised web and wide flanges, as clearly shown in Fig. 3, which cross-section. gradually merges into the solid cross-section. On the respectively opposite'crank arm faces the arm cross-section may be enlarged as required.

on the journals and pins, by first emplacing one/bearing half 7 through the open ends of the facing recesses 4 and by then turning it about the pin through 180, and by finally I laying on the other bearin half 8.

In multi-throw crank s afts with relativelydisplaced cranks the mounting of the This conformation of recess allows of the bearings or brasses being readily mounted axial sense by means of expansion rings "8',

asshown in Fig. 4t. The crank shaft with the bearing members t us in place can then readily be mounted in its case.

Fig. 5 shows my invention in connection With a twoethrov v crank construction. In multi-throw crank shafts the advantages set forth above," obviously, will still more be apparent, and the reduction of the shaft length will row proportionately.

What I c aim is:

1. A shaft having a substantially rectan-- rections about the shaft crank pin connecting the arms, the side faces of the latter having open ended recesses extending about said pin and journal portions, for the purpose specified.

3. A crank shaft comprising two parallel crank arms and a crank pin connecting the latter the side faces of said arms having-U shaped recesses extending in opposite diand pin for the purpose specified.

A crank shaft comprising two parallel crank arms and a crank latter, the side faces of said arms having U- shaped recesses extending longitudinally of the arms about the shaft and pin in opposite directions, for the purpose specified.

11 testimony that I claim the foregoing as my invention, I have signed my name.

DR. ALOIS RIEDLER.

pin connecting the 

